The immunization w/live, attenuated (Oka/Merck) varicella-zoster vaccine will reduce significantly the burden of illness associated w/HZ. This hypothesis will be tested by comparing the burden of illness due to HZ in the total population of vaccine and placebo recipients. The burben of illness due to HZ is defined by the areas under worst pain (rated on a 0 to 10 scale) versus time curves measured during the 6 month period following HZ rash onset in subjects who develop HZ. Subjects who do not develop HZ will be assigned a score of zero in the burden of illness analysis. The burden illness defined in this manner is sensitive to the incidence, the severity, and the duration of HZ-associated pain (149). The study is designed to have 98 percent power to detect a 50 percent reduction in mean burden of illness in the vaccine group relative to the placebo group. B. SPECIFIC AIM: The primary objective of this study is to determine whether immunization w/live-attenuated varicella-zoster vaccine (OKA/Merck Strain) can reduce the incidence and/or severity of herpes zoster (HZ) and its complications, primarily post-herpetic neuralgia (PHN), in persons 60 years of age and older. This will be accomplished by comparing a measure of the burden of illness due to HZ and PHN in vaccine and placebo recipients.